No worries, I momentarily forgot you haven't even seen it yet! You were taliking about converting to power trim, so I guessed your engine is manual, this is about adjusting the trim manually.
If you have manual trim, there is a long pin somewhere at the bottom of your clamps that has a selection of holes to put it in. It is what the leg etc rests against when it's in the "run" position. the SR4 has a slightly raked transom, so if you have the pin in the "bottom" hole, the engine is trimmed "fully down". Likewise if the pin is in the "top" hole it is as far out as it will go.
Full down will give heavy steering and won't be wonderfully fuel efficient. Full up and the prop will "let go" at the slightest provocation. Somewhere in the middle is the optimum for your boat. Previous owner may have it set up correctly, but alwways worth a wee experiment for your loading & driving style. (previous owner may have had three large friends & their diving kit aboard kind of thing......)
The trick is to move it up hole at a time until the prop starts to let go in fast corners. then drop it back down one. Trim is now as optimal as it's going to get.